Foetal medicine

Question 1

The three criteria for screening

Answer 1

Disease (common, serious, treatable), Test (accurate, reliable, inexpensive), Program (accessible, accepted, counselling)

Question 2

What is screened for in first antenatal blood test

Answer 2

• Anaemia
• Sickle cell, thalassaemia
• Infection
• Blood group and Rhesus D status
• Random blood sugar

Question 3

What are the measurements included in the first trimester screening for 21T

Answer 3

• Nuchal fold thickness
• beta-hCG
• Pregnancy associated plasma protein A (PAPP-A)

Question 4

What is the cutoff for high-risk of 21T after the first screening?

Answer 4

1:150

Question 5

When might the Triple/Quadruple test for 21T be done?

Answer 5

15-20 weeks if the mother is too late for the first trimester screening

Question 6

What is the sensitivity of the first trimester screening compared to the second trimester screening for 21T

Answer 6

1st = 90%
2nd = 60-75%

Question 7

What measurements are included in the Triple/Quadruple test for 21T?

Answer 7

Alphafetoprotein (AFP) - Low
beta-hCG - High
Oestriol - Low
Inhibin A - High

Question 8

What are the options for mothers who have 1:150 risk or higher for 21T?

Answer 8

Non-invasive prenatal screening - Free foetal DNA - 99% sensitive - private only so £300 charge
Chorionic Villous Sampling
Amniocentesis

Question 9

What is chorionic villous sampling, what is the miscarriage risk and when can it be done?

Answer 9

A small sample of the placenta is taken under US guidance, it carries a 2 in 100 risk of miscarriage and can be done after 10 weeks
11-13 weeks transcervical
>13 weeks transabdominal

Question 10

What is amniocentesis, what is the miscarriage risk and when can it be done

Answer 10

A small sample of the amniotic fluid is taken under US guidance, it carries with it a 1 in 100 risk of miscarriage and can be done after 15 weeks

Question 11

What infections are routinely screened for in the antenatal clinic

Answer 11

HIV, hepatitis B, rubella susceptibility and syphilis

Question 12

What are the risk factors for gestational diabetes

Answer 12

BMI >30 
Previous macrosomic baby (>4.5kg) 
Previous GDM 
Family history of DM 
At risk ethnicity

Question 13

What are the risk factors for pre-eclampsia

Answer 13

BMI >30
Age >40
Nulliparity or >10 years since last birth
Previous history of pre-eclampsia
Pre-existent hypertension or renal disease
Multiple pregnancy

Question 14

What are the methods of measuring foetal growth

Answer 14

Symphysio-fundal height should be measured at each antenatal visit after 24 weeks. Should roughly correlate with gestational age. If suspected IUGR, then serial USS may be needed

Question 15

What is the purpose of the 20 week scan

Answer 15

Find the placement of the placenta and identify any major abnormalities of the foetal anatomy